Detection, Confirmation and Characterization of Multi-planet Systems by Transit Time Variations

通过传输时间变化检测、确认和表征多行星系统

• 批准号: 362567553
• 负责人: Privatdozent Dr. Martin Pätzold
• 金额: --
• 依托单位: Rheinisches Institut für Umweltforschung (EURAD)
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2017
• 资助国家: 德国
• 起止时间: 2016-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/362567553?language=en
• 关键词: Detection; Confirmation; Characterization; Multi; planet

Multi-planet systems are crucial for the understanding of the formation and dynamical evolution of planetary systems. Only a small number of confirmed planets with true masses is known (compared to the number of all planetary candidates) because there is not enough telescope time available to cover all pending confirmations, in particular for faint stars. The mass determination for Earth- or Neptune-sized planets by radial velocity (RV) is in particular difficult with current telescopes and instrumental technique because of their small gravitational influence onto their host star. Thus it is not expected to get masses from all planetary candidates covering the full radii and orbital period ranges. Another method to characterize the planetary system and to complete this sample with regard to longer periods is the Transit Time Variation (TTV). This method uses only the information from the light curve and can detect, confirm and characterize transiting as well as non-transiting planets in multi-planet systems.Are there more undetected planets in a system? How closely packed are these systems? These questions may be answered by studying the orbital evolution of multi-planet systems: How do the orbital eccentricity and semi-major axis change with time? What are the influences of tides and general relativity on extremely short period TTV-planets? In recent TTV studies and in all existing TTV analysis software tools only the gravitational force is considered. This simplification may be valid for the majority of the analyzed systems but not for all. The inclusion of other forces is crucial for close-in planets (tides, general relativity), planets orbiting close to each other (planet-planet interaction) and for non-transiting planets perturbing the known transiting planet. By analyzing and comparing all forces together, the knowledge of the orbit, the stellar mass, the masses of the transiting planet and the perturbing planet may be verified and/or improved in particular for candidates difficult to be verified by RV observations. The questions above shall be answered by the analysis of light curves from existing planetary systems showing TTV as well as the search for more systems with TTV in ´new´ light curves from the Kepler and K2 missions. The already existing software package developed at RIU-PF shall become fully automated by implementing a Monte Carlo Markov Chain to search the whole parameter space for the best solution. Tides, general relativity and stellar oblateness shall be implemented in the orbit simulation for a full characterization of the planetary system. TTV is mostly the only chance to characterize a detected planetary system. The direct application, however, is the verification of transiting planets independent from ground-based observations. In consequence, TTV is also the detection of an unknown planet perturbing the known planet and therefore the detection of a multi-planet system which can be directly characterized by TTV.

多行星系统对于理解行星系统的形成和动态演变至关重要。仅知道少数带有真正质量的确认行星（与所有行星候选者的数量相比），因为没有足够的望远镜时间来涵盖所有待处理的确认，尤其是对于完美的恒星。当前的望远镜和器乐技术对径向速度（RV）对地球或海王星大小的行星的质量测定特别困难，因为它们对宿主恒星的引力很小。预计不会从所有行星候选者那里获得群众，涵盖了整个半径和轨道周期范围。表征行星系统并完成该样本的另一种方法是过境时间变化（TTV）。该方法仅使用来自光曲线的信息，可以检测，确认和表征多个平面系统中的非传输行星。是否在系统中还有更多未被发现的行星吗？这些系统的包装如何？这些问题可以通过研究多行星系统的轨道演变来回答：轨道偏心率和半肌轴如何随时间变化？潮汐和一般相对性对非常短的TTV行李箱的影响是什么？在最近的TTV研究和所有现有的TTV分析软件工具中，仅考虑重力。这种简化可能对大多数分析系统有效，但对所有系统无效。包含其他力对于近距离行星（潮汐，一般可靠性），旋转彼此绕行的行星（行星 - 平面相互作用）以及对已知过境行星扰动的非传输行星至关重要。通过分析和比较所有力，可以验证和/或改进轨道，恒星质量，恒星质量，过境行星和扰动行星的质量，尤其是通过RV观测来验证的候选者。上面的问题应通过对现有行星系统的光曲线进行分析来回答，显示了TTV的现有行星系统，以及从开普勒和K2任务中使用“ New”光曲线中使用TTV的更多系统。在RIU-PF开发的已经存在的软件包应通过实现Monte Carlo Markov链来搜索整个参数空间以找到最佳解决方案，从而完全自动化。潮汐，一般相对性和出色的涂抹应在轨道模拟中实施，以完全表征行星系统。 TTV主要是表征检测到的行星系统的唯一机会。但是，直接应用是对独立于地面观测的过境行星的验证。因此，TTV也是对已知行星扰动的未知行星的检测，因此可以检测多个星光系统，该系统可以直接以TTV为特征。